/*
 * Copyright (c) 2010, 2011, Oracle and/or its affiliates. All rights reserved.
 * ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 */

package java.nio.file;

import java.util.ConcurrentModificationException;
import java.util.Objects;
import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.InvalidObjectException;

/**
 * Runtime exception thrown if an I/O error is encountered when iterating over
 * the entries in a directory. The I/O error is retrieved as an {@link
 * IOException} using the {@link #getCause() getCause()} method.
 *
 * @see DirectoryStream
 * @since 1.7
 */

public final class DirectoryIteratorException
    extends ConcurrentModificationException {

  private static final long serialVersionUID = -6012699886086212874L;

  /**
   * Constructs an instance of this class.
   *
   * @param cause the {@code IOException} that caused the directory iteration to fail
   * @throws NullPointerException if the cause is {@code null}
   */
  public DirectoryIteratorException(IOException cause) {
    super(Objects.requireNonNull(cause));
  }

  /**
   * Returns the cause of this exception.
   *
   * @return the cause
   */
  @Override
  public IOException getCause() {
    return (IOException) super.getCause();
  }

  /**
   * Called to read the object from a stream.
   *
   * @throws InvalidObjectException if the object is invalid or has a cause that is not an {@code
   * IOException}
   */
  private void readObject(ObjectInputStream s)
      throws IOException, ClassNotFoundException {
    s.defaultReadObject();
    Throwable cause = super.getCause();
    if (!(cause instanceof IOException)) {
      throw new InvalidObjectException("Cause must be an IOException");
    }
  }
}
